One of the major obstacles facing wider adoption of CRISPR/Cas9 systems as a gene editing and gene therapy technique is the off target cleavage of DNA. In a report published in Science (http://www.sciencemag.org/content/early/2015/11/30/science.aad5227.abstract) MIT researchers used rational protein engineering to improve CRISPR/Cas9 specificity. Using the crystal structure of the CRISPR/Cas9 complex researchers identified a positively charged groove that is able to stabilize binding of negatively charged DNA. By changing three of the positive amino acids found in this groove to neutral amino acids the researchers reasoned that DNA binding would become more dependent on proper Watson-Crick base pairing between the CRISPR guide RNA and the targeted DNA. This improved Cas9, coined “enhanced specificity” SpCas9 or eSpCas9, eliminated 22 of the 24 off-target events observed when compared to wild-type Cas9 treatment.

Gene editing technology, such as CRISPR/Cas9 and TALEN systems provide the opportunity to edit not only the plants humans consume but animals as well. Gene editing technology is currently being applied to the cattle industry to create hornless dairy cows in order to prevent farmers from needing to dehorn their livestock. More immediately consumers will have access to salmon that has been modified in order to substantially increase its growth rate. Gene editing is also being used for therapeutic goals with pigs being altered to grow human organs that will not be rejected and to make malaria resistance mosquitoes all in an effort to improve human health. While these technologies provide many opportunities some scientist and activists are promoting caution while the FDA has yet to release guidelines for gene editing. In order for gene editing technology to become widely adopted scientist, the public, and government regulators will need to come to a consensus as to the extent to which this technology is used.

The battle for patents related to CRISPR/Cas9 technology is beginning to heat up. On February 11, 2015 the first CRISPR/Cas9 European patent was granted to the Broad Institute at MIT and Harvard and by October 26 nine different groups have filed oppositions. The fight over the CRISPR/Cas9 patents extends to the US where ~13 patents have been granted. In both the US and Europe these disputes are based around who invented the technology first with competing claims coming from both the University of California and the Broad Institute. With CRISPR/Cas9 technology opening up possibilities in agriculture and gene therapy this fight is set to continue for years to come.

In an effort to improve CRISPR/Cas9 targeting research at the University of Massachusetts Medical School combined the old with the new. Zinc Finger DNA editing was originally developed in the early 1990’s by combining the DNA binding Zinc Finger protein domain with the Fok1 nuclease domain. Since then researchers have developed tools to design zinc-finger binding domains to target specific DNA sequences. The researchers at the University of Massachusetts combined this ability with the new CRISPR/Cas9 system by fusing a Zinc Finger domain to Cas9 to enhance the specificity of DNA targeting. By combining these two different DNA targeting technologies the risks of off target effects.

Genetic therapy has reached a new milestone with one-year-old Layla seemingly cured of childhood leukemia. Layla was recently diagnosed with incurable leukemia and as a last ditch effort her parents and doctors received permission to try an experimental gene therapy treatment. Donor immune cells were edited with TALENs to seek out and kill only the leukemia cells in Layla’s body. Only a few months after the treatment Layla had no traces of leukemia in her body. While this treatment used an older, more expensive gene editing technique known as TALENs the advent of the cheaper and easier CRISPR/Cas9 technology may make more treatments like this a reality.

Each year thousands of people wait for a transplant organ. Pig organs have long been thought of as a potentially limitless source of transplant organs but research was slowed in 1998 when scientists discovered that the pig genome contains viral DNA that can infect and alter human cells. This obstacle may have recently been overcome when a single CRISPR/Cas9 system was used to alter 62 pig genes to deactivate this viral DNA. With further research gene editing technology could finally create the limitless supply of transplant organs needed.

The first US patent for CRISPR/Cas gene editing was awarded to Feng Zhang of the Broad Institute and MIT on April 15, 2014, however a second patent application was submitted seven months prior to Zhang’s by Jennifer Doudna of UC-Berkeley and Emmanuelle Charpentier of the Helmholtz Center for Infection Research in Germany. Both Doudna/Charpentier and Zhang had been working on CRISPR/Cas systems with the controversy over who owns the CRISPR/Cas Intellectual property stemming from the first date both groups published. Doudna was the first to demonstrate CRISPR/Cas systems ability to edit targeted DNA, however Zhang was the first to demonstrate that this technology can be used to edit human cells. Since both groups have set up competing companies the fight over who owns this intellectual property could continue in the courts for many years.

Scientists at the University of Pennsylvania have used an adeno-associated virus and CRISPR/Cas9 technology to correct a rare liver disease that results from a defect in the urea cycle. Interestingly, the researchers found that the treatment was more effective in newborn over adult mice. Further improvements of the efficiency of repaired DNA integration is needed before genetic treatments are available for humans. The original research can be found at http://www.nature.com/nbt/journal/vaop/ncurrent/full/nbt.3469.html.

Editas Medice is the latest CRISPR startup to go public and the first IPO in 2016. The IPO sold 5.9 million shares at $16 each, bringing in $94.4 million. Despite the promising IPO, the future of Editas may rest in the patent dispute currently playing out over CRISPR. Editas has licensed the technology from the Broad Institute, which is currently in a patent battle with UC-Berkley with the results from the dispute expected in 1-2 years.

The Human Fertilization and Embryology Authority in Britain have approved the use of CRISPR/Cas9 gene to edit viable human embryos. The approval is only for a single research group investigating embryonic development. Unlike in the US, in Britain all experiments using human embryos must be approved by the government, meaning this research will not lead to the routine editing of embryos.